Composite firearm barrel



NQv. 22, 1938. T. i. s. BoAK 2,137,259

COMPOS ITE FIREARM BARREL Filed Dec. 14, 1955 Patented Nov. 22, 1938 NITED srA'ras -AENT one CUMPOSITE'FIBEABM y1 Thomas I. S. Boek, Hamden, Conn., assignor to Winchester Repeating Arms Company, New Haven, Conn., a corporation of Maryland Application member/114, lass, semi No. 54,431; 2 claim. (ci. iz-ie) 'I'his invention relates to an improvement in Y rearm barrels, that is to say, riie barrels, shotgun barrels, etc., etc.

One of the -objects of the present inventionv 5 is to provide a firearm barrel having a superior surface finish of attractive and durable character and of adequate heat emissivity.

Another object is to provide a superior composite :dream barrel comprising an inner barrelbody and an outer finishing-shell of wrought metal coverinlg the barrel-body and gripping the same under tension. .l

A further object is to provide a superior composite irearm barrel comprising an inner barrelbody and an outer nishing-shell of wrought metal, which latter will remain in intimate engagement with the barrel-body despite such heating as will occur as an incident to the repeated ring of an arm of which the present improved composite barrel forms a part.

With the above and other objectsv in view, as vwill appear to those skilled in the art from the following, considered in conjunction with the accompanying drawing and appended diaims,

the present invention includes all features disclosed therein which are novel overthe prior art.

In the accompanying drawing:

Fig. 1 is a view in side elevation of a com posite rearm barrel embodying the present invention;

Fig 2 is an enlarged-scale transverse sectional view thereof, taken on any one of the lines 2-2 of-Flg. 1;

Fig. 3 is a perspective view of the barrelbody; and ,Y

Fig. 4 is a similar view of the finishing-shell.

The present invention contemplates applying a wrought metal nishing-shell to a barrel-body in such manner that the finishing-shell will remain in intimate contact with the barrel-body in all normal use to which the composite barrel may be put, and by meansv of which a superior, durable and attractive finish may be imparted to the surface of the barrel-unit. Preferably, the

finishing-shell is formed of a wrought metal of a character dissimilar to the metal from which the barrel-body is formed, being formed, for instance, of brass, copper, aluminum, etc. It has been found that nishing-shells of wrought aluminum or aluminum alloys provide thedesired characteristics to a high degree.

For the purpose of an understanding of the present invention, a rie barrel has been chosen for illustration and description, though it will be understood that the invention is equally applithreaded shank i3, by means of which the barrel 10 may be attached toa suitable frame or receiver. The said externally-threaded shank i3 is of smaller diameter than the rear end of the main portion of the barrel-body ill `and results in the production of a rearwardly-facing seating-shouli6 der i4 which is of larger diameter than is the forward face or terminal i6 of the barrel-body (F18. 3).

Over the barrel-body I is mounted a wrought metal finishing-shell i6 which may be formed 20 of wrought aluminum, brass, copper, or such other materialL as is capable of receiving and holding. the desired iinish, and may, for instance, be of a thickness of about .015".

As before indicated, the finishing-shell is de- 25 signed to closely embrace land grip the exterior surface of the barrel-body i0 and to remain thereon under a contracting tension during the normal use of the composite barrel of which the nishing-shell forms a part. Various methods 3g which will be apparent to those skilled in the art may be employed for applying the wrought metal nishing-shell IG'to the barrel-body l0. It has been found that the application of the finishing-shell may be economically accomplished 35 by drawing the ilnishing-shell so as to provide it with an interior contour substantially conforming to the exterior contour of the barrel-body l0, but of lesser diametrical dimensions than the same. The finishing-shell may now be heated 4p to a degree sumcient to expand it, so that its interior diameter will exceed the exterior diameter of the barrel-body I 0, after which the said finishing-shell may be slipped over the relatively-cold barrel-body. Upon cooling, the iin- 45 ishing-shell will shrink upon and tightly grip the barrel-body I0.

Preferably, when initially applied, the finishing-shell will exceed in length the length of the barrel-body proper, and after it has been shrunk 50 in place,.the respective opposite ends of the finishing-shell may be out ofi' ush with the shoulder i6 and the i'rontface I5 of the barrel-body, or, if desired, portions of the finishing-shell may be the composite barrel in an electrolyte. such, for

instance, as sulphuric acid. and connected in an electric circuit in such manner as to constitute an anode. Now when suitable electric cu'rrent is caused to pass through the bathin which a`suitto its low light-reflecting power.

able cathode. such, for instance. as lead, is also immersed, an oxide coating wiligbefformed on the aluminum surface of the composite, barrel forming the anode. which coating will in the main be composed of common oxide ot aluminum (A1201) plus aluminum hydroxide and aluminum sulphate. The coating thus applied will be almost invisible and will have a very high heat emissivity. The coating referred to will, in addition, be extremely resistant to abrasion.

While various colors may be applied to the aluminum ilnishing-sheli I l after the same has been oxidized as described. it will be sufficient for the present purpose to refer to the blacking of the exterior surface of the composite barrel, in asmueh as blacking is the most desirable, owing The oxidecoated surface of the composite barrel, which coating is indicated by the stippling l1 in Fig. 2, may be blacked by immersing the same in a solution of cobalt acetate or in a solution of a nitrate or chloride of cobalt and thereafter immersing the barrel in a solution of-ammonium sulphide. For the present purpose. black is to be considered as a color.

The composite barrel. bled and nished as above described; will possess an exterior finish oi deep black which will be highly resistant to abrasion and which, owing to its high heat emissivity, will assist in the dissipation of heat from the barrel-body. Furthermore, the nishing-shell i6 will, under all normal conditions of use, remain in intimate contact with the surface of the barrel-body I0. despite temperature rises occasioned therein by repeated firing of an arm of which the barrel may form a part.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivaiency range of the appended claims are intended to be embraced therein.

' I claim:

l. A compositeV barrel for firearms. comprising: a relatively-thick tubular barrel-body and a relatively-thin tubular heat-dispersing and finishing shell composed of dierent metal than the said barrel-body and having a greater degree of thermal conductivity than the same, the said heat-dispersing and finishing shell having its outer surface oxidized and permeated with a coloring material of a character serving to increase the heat emissivity of the said shell.

2. A composite barrel for rearms, comprising: a relatively-thick tubular barrel-body and a re1- atively-thin tubular wrought-metal heat-dispersing and iinishing shell having a greater degree of thermal conductivity than the said barrel-body and composed primarily of aluminum and applied over the said barrel-body in intimate thermal engagement therewith and having an outer surface composed mainly of aluminum oxide with a coloring material permeated thereinto.

THOMAS I. S. BOAK. 

